Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Observational Study
. 2025 Mar 27;17(7):1160.
doi: 10.3390/nu17071160.

Effects of Maternal Vitamin D Levels on Prematurity: Feasibility Study in a Multicenter Observational Pilot

Olivia Barbosa  1   2   3 , Ana Teresa Freitas  4   5 , Marta P Silvestre  6   7 , André Moreira-Rosário  6   7 , Pedro Aguiar  8 , Ana Isabel Régua  9 , Tatiana Madaleno  10 , Manuela Almeida  11 , Dulce Cruz  1   2
Affiliations
Observational Study

Effects of Maternal Vitamin D Levels on Prematurity: Feasibility Study in a Multicenter Observational Pilot

Olivia Barbosa et al. Nutrients. .

Abstract

Background: Numerous studies have shown that hypovitaminosis D is linked to adverse maternal and infant health outcomes, such as intrauterine growth restriction, preeclampsia, cholestasis, hypertension, and gestational diabetes, all of which are potential causes of prematurity. Recognizing the significance of this issue and its impact on maternal-infant health, the VitDTracking research project was designed and registered on 4 March 2024, in the ClinicalTrials.gov database (Identifier: NCT06292195). The project includes a large-scale multicenter observational study, targeting a minimum initial sample size of 1800 participants. This paper describes the pilot study aimed at assessing the feasibility of the full-scale study. Methods: A multicenter observational pilot study was conducted in public health organizations in the Alentejo region, adhering to the research protocol. Data collection included 67 parameters: 37 obtained from a questionnaire and 30 from clinical records, with particular focus on maternal 25(OH)D levels and maternal-infant health outcomes. Feasibility was assessed through predefined outcome indicators and success criteria. Results: The pilot study enrolled 30 pregnant women and successfully met all feasibility criteria. The global recruitment rate was 73.17%, with an eligible recruitment rate of 88.2%. The refusal rate was low (11%), and adherence, retention, and completion rates were all 100%, indicating strong participant engagement. The questionnaire comprehension rate was 86.6%. Participating centers demonstrated the capacity to implement the study, adhering to the protocol with a compliance rate exceeding 90%. The study also highlighted a concerning prevalence of hypovitaminosis D and identified cases of premature birth and miscarriage. Conclusions: The pilot study confirmed the feasibility of recruitment methodologies and procedures, supporting the implementation of the large-scale observational study. The planned study will recruit approximately 1800 pregnant women to achieve an eligible cohort of 1000 samples, and a statistically significant final sample of 100 cases meeting the prematurity criterion.

Keywords: feasibility study; maternal vitamin D levels; prematurity; public health.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
Pilot study protocol flowchart.
See this image and copyright information in PMC

Similar articles

See all similar articles

References

    1. Van der Pligt P., Willcox J., Szymlek-Gay E.A., Murray E., Worsley A., Daly R.M. Associations of Maternal Vitamin D Deficiency with Pregnancy and Neonatal Complications in Developing Countries: A Systematic Review. Nutrients. 2018;10:640. doi: 10.3390/nu10050640. - DOI - PMC - PubMed
    1. Roth D.E., Abrams S.A., Aloia J., Bergeron G., Bourassa M.W., Brown K.H., Calvo M.S., Cashman K.D., Combs G., De-Regil L.M., et al. Global prevalence and disease burden of vitamin D deficiency: A roadmap for action in low- and middle-income countries. Ann. N. Y. Acad. Sci. 2018;1430:44–79. doi: 10.1111/nyas.13968. - DOI - PMC - PubMed
    1. Hollis B.W., Wagner C.L. Substantial vitamin D supplementation is required during the prenatal period to improve birth outcomes. Nutrients. 2022;14:899. doi: 10.3390/nu14040899. - DOI - PMC - PubMed
    1. Lee J.M., Smith J.R., Philipp B.L., Chen T.C., Mathieu J., Holick M.F. Vitamin D deficiency in a healthy group of mothers and newborn infants. Clin. Pediatr. 2007;46:42–44. doi: 10.1177/0009922806289311. - DOI - PubMed
    1. Christoph P., Challande P., Raio L., Surbek D. High prevalence of severe vitamin D deficiency during the first trimester in pregnant women in Switzerland and its potential contributions to adverse outcomes in the pregnancy. Swiss Med. Wkly. 2020;150:w20238. doi: 10.4414/smw.2020.20238. - DOI - PubMed

Publication types

Associated data